Valve for rock drills



June so, 1925. 1,543,816

L. C. BAYLES VALVE FOR ROCK DRILLS Original 189 Oct. 16, 1922 INVENTOR I y, .W H15 ATrOR EY .Zezrid By 1a;

Patented June 30, 1925.

pairs sra'rss LEWIS o. EAYLEs, or EAST-0N, PENNSYLVANIA, AssIeNon r0 iNGEnsoLL-E-ANn COMPANY, or JEnsEv CITY, NEW JERSEY, A CORPORATION on NEW JEEsEY.

VALVE FOB ROCK DRILLS.

Original application filed October 16, 1&22, Serial No. 594,728. Divided and this application filed November 19, 1924.

To aZZ whom it may concern:

' Be it known that I, Lnwis C. BAYLEs, a citizen of the United States, and resident of Easton, county of Northampton, and State of Pennsylvania, have invented a certain Valve for Rock Drills, of which the following is a specification, accompanied by drawings.

This application is a division of my copending U. S. application Serial No. 594,- 728 filed October 16, 1922.

This invention relates to rock drills, but more particularly to a differential spool type valve designed to admit and exhaust motive fluid to and from the percussive element of the rock drill. In the present valve one enlarged end head is designed to have an actuating face and separate opposed holding faces for holding the valve in one direction or the other, and the action of a valve thus constructed will be quick and positive and the valve will also possess the desirable qualities of strength and lightness of weight, thus resulting in high drilling efficiency. 7

Other objects will hereinafter appear in the following specification and accompanying drawings, illustrating the invention in its preferred forms.

Figure 1 is a diagrammatic longitudinal sectional elevation of a part of a rock drill showing a differential spool valve embodying the invention, and

Figure 2 is a diagrammatic longitudinal sectional elevation of a part of a rock drill showing amodified form of the valve.

Referring to the drawings, the invention is shown embodied in a rock drill of the hammer type, having a cylinder A and a valve chest B. A. hammer piston C, having a cylindrical forward extension, reciprocates within the cylinder for delivering impact blows upon a drill steel. A front cylinder washer D, only a portion of which is shown, forms a' closure for the forward end of the cylinder, and a back head, as

'idicated at E,serves as a closure for the rearward end of the cylinder.

A. valve chamber F having an enlarged bore, preferably at one end, contains a valve G, shown in this instance of the differential spool type. Motive fluid is preferably ad mitted into the chamber from a source of supply (not shown) through a plurality of Serial No, 750,766.

ports, in this instance, an inlet port H communicating with the smaller bore of the chamber F, and another inlet port J in communication with the enlarged bore of the chamber F. Exhaust of motive fluid from the drill is in this instance effected through a central exhaust port K communicating with the smaller bore of the chamber F.

Admission and exhaust of motive fluid to and from the cylinder A is controlled by the valve G. To this end the valve is provided with a central head L for controlling the enhaustport K, and one head 0 of the same diameter as the head L provided with an actuating face P at its and, controls the admission of motive fluid to one end of the cylinder. The admission of motive fluid to the other end of the cylinder is'controlled by an enlarged valve head Q, provided with an actuating face R, and holding faces S and T. A plug U, having a reduced extension, forms a closure for one end of the chamber F, and cooperates with the valve head Q, for forming an actuating pressure chamber V and a holding pressure chamber WV.

Supply passages X and X connect the valve chamber with the forward and rearward ends respectively of the cylinder, and passages: Z and Z effect communication between the chambers in which the actuating faces P and Q, of the valve are located, and points in the cylinder between the passages X and X. A passage Y is in this instance shown connecting the holding pressure chamber W with the passage X.

In the operation of the valve, assuming that the valve G and the piston C are in the positions indicated in Figure 1 of the drawings, motive fluid is admitted from the inlet port H and passes through the supply passage X into the front end of the cylinder A. Simultaneously, motive fluid will pass through the passage Y connecting the supply passage X with the holding pressure chamber N, and will hold the valve in its thrown position until the piston G uncovers the passage Z, and exert pressure against the actuating face P and this pressure preponderates over the pressure in the holding pressure chamber TV at the opposite end of the valve permitting fluid to enter the passage Z and moves the valve to its opposite position. The inlet port'I-I will then be closed by the valve head 0, and the central valve head L will open comunication between the supply passage X and the exhaust port K, and permit the motive fluid in the forward end of the cylinder A to escape to atmosphere. At the sametime the valve head Q will open communication between the inlet port J and the supply passage X, and since the diameter of the head Q is larger than that that or the central head L,

porta. and the central exhaust port K to atmosphere, thus completing thecycle of operations.

The holding and actuating faces of the enlargedvalve head may, however, be reversed as in Figure 2, in which the outer face 6 of the enlarged head Q serves as the actuating face, and the face 0 of the reduced extension cZ forms a holding area for holding the valve in one position. In this instance, a plug a, forming a closure for the end of the chamber F, is provided with a holding pressure chamber f to receive the extension (Z. Otherwise the construction and operation of the valve are the same as described in connection with Figure 1 I claim:

1. In a rock drill, the combination of a cylinder, a reciprocatory piston within the cylinder, a valve chest having a valve chamber with an enlarged bore at one end, inlet ports for the valve chamber, an Xhaust port for the chamber communicating with t-l e atmosphere, and a valve within the chamber to control the exhaust and inlet )orts, said valve having a central head, one nd head of the same diameter having an actuating'face, and another enlarged end head tuating face and opposed holding faces.

2. Ina rock drill, the combination of a cylinder, a reciprocatory piston within the cylinder, a valve chest having a valvechamber with an enlarged bore at one end, inlet ports for the valve chamber, an exhaust port for the chamber communicating with the atmosphere, and a valvewithin the chamber, said valve having a central head, one end head of the same diameter having an actuating face, another enlarged end head having an actuating face and opposed holdingfaces, and a plug cooperating with the enlarged head of the valve for forming actuatlng and holding pressure chambers.

3. In arock drill, the combination of a cylinder, a reciprocatory piston within the cyl-i inder, a. valve chest having a valve chamber with an enlarged bore at one end, inlet ports for the valve chamber, an exhaust port for the chamber communicating with the at mosphere, and a valve within the chamber, said valve having a central head, and an end head of the same diameter with an actuating face, an enlarged head with an actuating face and opposite holding faces, a plug for sealing one end of the valve chamber, and cooperating with the enlarged head of the valve to form actuating and holding pres sure chambers, said valve chamber being provided with ports and passages foradmitting and exhausting motive fluid to and from the cylinder and for actuating and holding the valve.

.In testimony whereof I have signed this specification.

Lnw s e. BAYLEQ;

ith an ac- 

